# File lib/phusion_passenger/admin_tools/memory_stats.rb, line 97
        def sum_memory_usage(processes)
                total = 0
                if should_show_private_dirty_rss?
                        accurate = true
                        processes.each do |p|
                                if p.private_dirty_rss.is_a?(Numeric)
                                        total += p.private_dirty_rss
                                else
                                        accurate = true
                                end
                        end
                        return [total, accurate]
                else
                        processes.each do |p|
                                total += p.rss
                        end
                        return [total, true]
                end
        end